The inspection of components, or objects, for defects using an ultrasonic time of flight technique is well known. In this technique two ultrasonic probes are used, with one ultrasonic probe located either side of the defect. The ultrasonic time of flight technique has the capability of detecting defects in the inner blend radius region and outer blend radius region of the welded interconnection between the inlet, or outlet, nozzle and the nuclear reactor pressure vessel.
The welded interconnection between the inlet, or outlet, nozzle and the nuclear reactor pressure vessel is not a uniform, or regular, geometric shape. This interconnection is an interconnection between a large diameter vertical cylinder, the nuclear reactor pressure vessel, and a small diameter horizontal cylinder, the inlet or outlet nozzle. The interconnection produces a saddle shaped corner, or bend, wherein the angle of the bend can vary from 90.degree. to approximately 130.degree. dependent upon the radial displacement about the axis of the small diameter horizontal cylinder.
However, practical implementation of the ultrasonic time of flight technique for use in detecting defects in weld joints between inlet, or outlet, nozzles and the nuclear reactor pressure vessel is difficult and costly. This is due to the fact that large numbers of beam angles and/or extremely complex probe array and scanning patterns are required to inspect the complex geometry of this interconnection.